Clean mushroom caps. Using a melon baller, scoop out and discard insides of mushroom caps.
In a medium bowl, combine mushroom caps, olive oil, and ⅛ teaspoon salt, gently tossing to coat. Place mushroom caps 2 inches apart on prepared baking sheet.
Bake until mushrooms are dark and tender, approximately 10 minutes.
Meanwhile, in a medium sauté pan, melt butter over medium heat. Add shallot, cooking until tender, stirring occasionally, 8 to 10 minutes. (Reduce heat, if necessary, to prevent burning.) Add lima beans, corn, cream, thyme, remaining ¼ teaspoon salt, sage, and pepper. Stirring occasionally, cook until mixture (succotash) is very hot.
Divide succotash among prepared mushroom caps.
Garnish with paprika, if desired.
Serve immediately.
Notes
Make-Ahead Tip: Succotash can be prepared a day in advance, covered, and refrigerated. Warm gently before using.
Recipe by TeaTime Magazine at https://teatimemagazine.com/succotash-stuffed-mushrooms-recipe/